Since forum is full of posts about broken main story i made a tutorial about fixing some of the stages.
Message Across Tamriel bug:
http://tamrielfoundry.com/topic/final-main-quest-messages-across-tamrile-bug/
Short version:
You do NOT need to do this quest to advance to Cold Harbour/VR.
- Port to a guildmember/friend who is already in Cold Harbour
- Enter the main City and start the quest from the woman at the south entrance
- voilà. you just started the last main quest which will lead you to VR content
The quest
"Army of Meridia" IS the main quest but ofc you will see it as a Coldharbour quest and ofc will be bugged couse you are not suppose to be there.
Here`s the solve to "Army of Meridia" bug after you finish it:
Broken q: Army of Meridia
Even if you save the king quest will still send you to save him.
On the map will show you a sign near a tent close to Library of Dusk waypoint where you won`t find the king.
How to:
Check if you completed quest on the 3 towers:The Lightless Oubliette, The Black Forge and The Great Shackle.
If all towers looks "completed" on map then:
Go in town (The Hollow City) and search a guy called Groundskeeper on the stairs of main castle.
Quit The Army of Meridia quest and talk to him.
He will give you a mix of FAILED, COMPLETE, FAILED.....and will start the next stage of quest.
Next you will be stuck in Library where you won`t be able to open a door:
http://forums.elderscrollsonline.com/discussion/80894/the-final-assault-open-the-library-gate-bug#latest
Here`s the library problem solved
Maybe you will be stuck in the final fight with MolagBal:
http://forums.elderscrollsonline.com/discussion/88091/god-of-schemes-bug#latest
Solved too
Feel free to add more if you know and i`ll stick them in here.
Hope will solve your problem faster than a ticket

GLHF